Construction of ways for launching vessels.



W. GATEWOOD.

CONSTRUCTION OF WAYS FOR LAUNCHING VESSELS.

APPLICATION HLED JULY 12, I917.

Patented Jan. 28, 1919.

Witness In min: m. I-nmuma. mummawu n I;

WILLIAM GATIEWOOD, NEWPORT NEWS, VIRGINIA.

CONSTRUCTION OF 'WAYS FOR LAUNGHING VESSELS.

Specification of Letters Patent.

Patented Jan. 28, 1919.

Application filed July 12, 1317. Serial No. 180,180.

To all whom it may concern:

B k ow that W I M G W a citizen of the United States of America,

residing at Newport News, in the county of Warwick and State ofVirginia, have invented certain new and usefullmprovements inConstruction of Ways for Launching Vessels, of the following is aspecificat1on.

The present invention relates to improvements in the construction ofways for launching essel Of a l typ and ha for i iec t9! d stribu e hpress es 1. 1 1 h o tQm O h Ve sel, to lesscn' hc i k of injury to the.strucbl re of the vessel and to obviate h ne e i y fo ntern l h r torediltethe a dun 9f eifa 'shor s r q ir I s'we l' aown tha he ll ill yfor vessels can provi a: dist uti the pre su es" t,v e, far rl pp ts' byh ting of a considera le amount of wood with the end grain fore aft ortransverse and 'i" i't .a s 'iha th qrwar a of h p p i l ild a t e ah fthe ess l lif s nd he'pr sllltc ll be dis b d- It is well known; also,thatthe launching Ways for la e Ve se n lude f ther P Q- Y si r di t ibuin hese Pres r s y means of special strips of soft wood known ascrushing s s 9 by ther special nsane It'i s well known, also, that underthe botm o essel he p essure a e iab e to bem sxcessivaover the aiit qed e d of the groundways during the progress of the launching especiallyat the time when the moment against tipping hQQOIIlQS small. In theconstruction bi the ways for endwise l nch g; h w ve ther i usua rylittle space in which to fit at grain wood under the bottom of a vesselwhere these Pr sures a e greates and i fth l f e Se1s laborate internalshorin s t are; to a; he purpose (of t a sm t f/se x cs i 'l' a Pressurend o Pr venting ocal deforma ons I have, dis overed t a the empir Psures Iunder the bottom of vessels: during laiinchinginaylbe distributedand the risk of local defo'rmation of the bottom greatly reduced by'fitting crushing strips of suitable material in the lannching cradlewherever the excessive pressures are likely to be experienced.

'The efficiency of these crushing strips is due to a conditionwhich isnot generally rec ognized, which is that the vessel during launching issubjected to forces which produce bending of the vessel as a Whole. Thisbending greatly increases the pressures over the outboard end of thegroundways, and would cause a concentration of the portion of the weightof the vessel which is carried by the ways at two pairs of points, theoutboard end of the groundways and the forward end of the fore puppets,were it not for the local settlement and deformation of the ways andcradles. The local deformation of the cradle which can be obtained bystrips suitably arranged to crush when a certain intensity of pressureis reached under the bottom of the vessel serves to distribute thepressures over a greater length of the bottom, and to revent more than alimited increase over the intensity of pressure at which the stripsbegin to crush, with the consequent elimination of local deformation ofthe structure of the vessel which might be caused by the greaterintensity and concentration of pressure.

Referring to the accompanying drawings forming a part of this inventionFigure 1 is a profile of a vessel during process of endwise launching;'

Fig. 2 is a similar View of the vessel at a later period during theprocess of launching;

Fig. 3 is a fractional view showing the general arrangement of thecrushing strips before launching; and

Fig. 4 is a similar view showing the crushing of the crushing stripsduring the period of launching represented in Fig. 2.

Fig.1 indicates how the reactions on the ways would be concentrated bythe bending of the vessel if'the ways were rigid and the cradleincompressible, while Fi 2 indicates more particularly how the reactionwould be concentrated at the outboard end of the groundways at the timewhen the moment against tipping becomes small.

1 is the vessel, 2 the cradle, and 3 the forward end of the cradle. lindicates the groundways and 5 the'outboard end of the groundways.

As the midlength of the vessel approaches the outboard end of thegroundways, and the vessel'has slid to a position where the morncnt aainst tipping becomes small, a considerable part of the pressure isconcentrated at the outboard end of the groundways, indicated by thearrow at 7, while only a very small part of the pressure is carried bythe remainder of the ways, indicated by the arrow 6.

In Figs. 3 and 4; the bottom of the vessel is indicated by the numeral8. 9 is the packing in the cradle, 10 represents the crushing strips, 11the string piece above the wedges, 12 the wedges and 13 the sliding way.

The crushing strips may be made of several different kinds of wood, suchas white pine, yellow pine, and cedar, or indeed, of manufacturedmaterial, but it is recommended that to Obtain the best results thematerial selected be uniform in character with grain flat, and have aconsiderable range of compression for a small increase in pressure. Onthis latter account, oak, for instance, does not seem to be a suitablematerial.

The size, spacing and distribution of the crushing strips may. vary tosuit in each particular case, but it is recommended that to.

obtain the best results, crushing strips be placed under the transverseframing of the vessel and under such longitudinal framing as may besufficiently rigid to withstand the pressures, and that the area of thecrushing strips be proportioned to the pressure to be transmitted sothat the strips will crush as intended, and that the thickness be suchas calculations and experience indicate to be necessary to obtain thedesired amount of crushing. Crushing strips of uniform size may be usedand the spacing varied to suit the pressures to be transmitted. They maybe fitted in one or more layers.

A crushing strip which has considerable height relative to its widthwill start to crush under a smaller load than a strip of the same width,if the height is the same as or less than the width. In the drawings theheight of the strips is somewhat exaggerated for the purpose of makingthe crushing more apparent to the eye. In practice, the strips could beof any proportions which it might seem desirable to use, but probablytwo layers would be used where the height would exceed one and a halftimes the width if only one layer were used.

The longitudinal extent of the crushing strips may vary, but it isrecommended that they be fitted as far forward and aft under the bottomas experience and calculations would indicate the excessive pressuresare likely to occur during the launching. About 30% of the length of thevessel each way from amidships will usually be a sufficient extent,although they may be fitted for the full extent of the cradle withadvantage.

Line 14 indicates the bearing of the sliding way on the ground wayobtained by the crushing of the crushing strips 10.

It is thus seen that by the use of crushing strips it is possible tosupport the vessel with a smaller amount of wood and at considerablysmaller cost than is possible with the usual fittings and that by thepro per selection of the material and judicious .distribution of thestrips the local crushing factors may be so chosen in. accordance withthe pressures of reaction found by calculation and experience as toinsure a fair distribution of the reactions over the bottom or aconsiderable length thereof. It is obvious that by proper dispositionand arrangement the reactions on the vessel will be likewise fairlydistributed over a considerable length of the body of the vessel so thatnormally the necessity for internal shoring is obviated.

However, internal shoring may be resorted to in certain cases inconjunction with the crushing strips and the use of such shoring dependson the rigidity of framing of the vessel, as the crushing strips serveprimarily todistribute the pressures, and the 85 reduction in the totalpressure obtained by their use is likely to be relatively small.

There is an advantage in fitting the crush ing strips in thedistribution of the excessive pressures which might be caused byirregularities in the surface of the groundways. Also when crushingstrips are used, the length of the groundways may be decreased, and themoment against tipping reduced over what would otherwise be considerednecessary.

There is advantage in fitting crushing strips in the cradle which wouldaccrue, even where the strips do not crush, and that is the saving inthe amount of material used 100 in the construction of the ways. It isobviously unnecessary, also, to fit the packing against the bottom overthe ways with care except under the more rigid parts of the bottom andas necessary to transmit the j pressures to the crushing strips, andsome of the packing as usually fitted might be omitted without danger ofinjury to the bottom and with advantage in regard to cost.

In the claims the fore puppets are considered about one-eighth thelength of the cradle and the main portion of the cradle about threefourths the length of the cradle, the remainder being taken up by theafter puppets.

What I claim is 1. The method, in launching vessels, of distributingpressures over the groundways which consists in placing crushing stripsunder the vessel and so positioning such strips 2 along the length ofthe vessel including at least a part of the main portion thereof thattheir crushing will relieve the excessive pressures occurring atdifferent points under the bottom of the vessel during the process of 12launching. 1

2. A cradle for launching vessels comprising crushing strips distributedover a considerable length of the cradle including at least a part ofthe main portion thereof to 30 form a crushing area ofiering differentre sistance in different parts, said strips being constructed andarranged to crush when, during the process of launching, pressure isconcentrated on a portion of the said area.

3. A cradle for launching vessels comprising crushing strips distributedover a considerable length of the cradle including at least a part ofthe main portion thereof to form a crushing area ofiering different resistance in difierent parts, the part ofiering the least resistancebeing constructed and arranged to yield when, during the process oflaunching, pressure is concentrated upon it.

4:. Launching Ways provided with crushing strips in the main portion ofthe cradle.

5. Launching ways provided with crushing strips in the main portion ofthe cradle,

in conjunction with crushing strips in the fore puppet.

6. Launching ways provided with crushing strips for the full length ofthe cradle.

7. Launching ways provided with crushing strips in the main portion ofthe cradle, the proportionate area of the crushing strips increasingfrom aft forward.

8. Launching ways provided with crushing strips in the main portion ofthe cradle, the proportionate area of the crushing strips increasingfrom aft forward, in conjunction with crushing strips in the forepuppets, the proportionate area of which increases from forward aft.

In testimony whereof, I aflix my signature.

WILLIAM GATEWOOD.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents.

Washington, D. 0.

Correctionsin Letters PatentNo. 1,292,754.

It is hereby certified that in Letters Patent N 0. 1,292,754, grantedJanuary 28,

' 1919, upon the application of William Gatewood, of Newport News,Virginia, for

an improvement in Construction of Ways for Launching Vessels, errorsappear in the printed specification requiring correction as follows:Page 1, lines 20, 24, 66; page 2, lines 110, 115; page 3, lines 20, 31,claims 5, 8, for theword puppets read poppets; page 1, line 55, forfeificiency read eficacy, and line 110, strike out the word at; and thatthe said Letters Patent should he read with these corrections thereinthat the same may conform to the record of the case in the PatentOfiice. I

Signed and sealed this 25th day of March A. D., 1919.

R. F. WHITEHEAD,

Acting Commissioner of Patents.

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